Know-Nothing movement

The great increase in immigrants to the US in the 1840s and especially after 1846 encouraged nativism (favoring the interests of established inhabitants over those of immigrants), anti-foreign, and anti-Roman Catholic feelings. In cities where Catholic, Irish and German immigrants had concentrated and been organised, local Protestant nativistic societies were formed to uphold a racist Anglo-Saxon Protestant viewpoint. The American Republican party, formed in New York in 1843, became a national party at its Philadelphia convention in 1845. Many Orders emerged, such as the Order of United Americans and the Order of the Star-spangled Banner. These organizations were highly secretive, all inquiries of supposed members were met with a statement that "I know nothing". Hence members were called Know-Nothings, although there was never a organization bearing that name.

Efforts were concentrated on electing only native-born Americans to office and on pushing for a 21-year residence qualification for citizenship (up from five years). Growing rapidly, the Know-Nothings allied themselves with the group who followed Millard Fillmore and almost captured New York State in the 1854 election, whilst doing well in Massachusetts and Delaware and had successes in other northern states. The disintegration of the Whigs over slavery aided them. In 1854 they looked toward extension into the South, and in the following year they assumed the name American party and ditched much of their secrecy.

But in June 1855, a crisis developed; at a meeting of the national council a pro-slavery faction seized control and adopted a resolution calling for the maintenance of slavery. The slavery issue, after the passage of the Kansas-Nebraska Act, split apart the Know-Nothing movement as it had the Whigs. The anti-slavery members joined the Republican Party. Millard Fillmore, the American party candidate for President in 1856, polled 21% of the vote but only won the State of Maryland. The national strength of the Know-Nothing movement rapidly declined thereafter and vanished after the 1860 elections, although their ideas lingered on in the Republican Party.